[autotests] Destroy main window in ToplevelOpenCloseAnimationTest::testDontAnimatePopups

Summary: Be nice and destroy all created windows in testDontAnimatePopups.

Test Plan: The test still passes.

Reviewers: #kwin, davidedmundson

Reviewed By: #kwin, davidedmundson

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D18037

autotests/integration/effects/toplevel_open_close_animation_test.cpp

@@ -208,6 +208,10 @@ void ToplevelOpenCloseAnimationTest::testDontAnimatePopups()
     popupSurface.reset();
     QVERIFY(popupClosedSpy.wait());
     QVERIFY(!effect->isActive());
+
+    // Destroy the main window.
+    mainWindowSurface.reset();
+    QVERIFY(Test::waitForWindowDestroyed(mainWindow));
 }
 
 WAYLANDTEST_MAIN(ToplevelOpenCloseAnimationTest)